新型1-烷基-2,3-二甲基咪唑六氟磷酸盐离子液体/过氧化氢酶电极电化学性能研究与应用

Study on electrochemical properties of novel 1-alkyl-2,3-dimethylimidazole hexafluorophosphate ionic liquid/catalase electrodes and their application

合成了5种新型1-烷基-2,3-二甲基咪唑六氟磷酸盐类离子液体,并以离子液体为介质制备空白电极及过氧化氢酶电极。采用循环伏安法研究电极电化学行为,结果表明离子液体有优良的电化学性质。离子液体空白电极的基体峰电流都在数nA范围内,电化学窗口大于4V;不同离子液体酶电极的电化学行为存在明显差异。在5种离子液体中,仅有1-戊基-2,3-二甲基咪唑六氟磷酸盐能很好地保持酶活,呈现灵敏的电化学响应。此外,该酶电极还具有良好的稳定性,4℃保存30天后,电化学性质没有明显变化。在0.1mol/L的H3PO4缓冲溶液(pH7.0)中,该酶电极还原峰电流随溶液中H2O2浓度的增加而增大。当H2O2浓度在3.17×10-6～12.4×10-6mol/L之间,酶电极的还原峰电流符合线性关系,其检出限为1.1×10-6mol/L。方法已用于环境水中痕量H2O2的测定。

Five novel 1-alkyl-2,3-dimethylimidazole hexafluorophosphate ionic liquids were synthesized and developed as media to fabricate blank working electrodes and catalase electrodes in this work. The electrochemical performance were investigated by cyclic voltammetry, aod the results indicated ionic liquids possessed favorable electrochemical propesties. Among these blank electrodes, background current was only several nanoamps, and their electrochemical windows were more than 4 V. It was found the species of ionic liquids affected electrochemical performance of the enzyme electrodes obviously. Only enzyme electrodes based on 1-amyl-2,3-dimethylimidazole hexafluorophosphate ionic liquid can preserve good enzyme activity and produce a sensitive electrochemical response. Moreover, the above enzyme electrode was very stable, its electrochemical properties remain almost unchanged for 30 days at 4℃. In pH 7.0 phosphate buffer solution, the reduction peak current increased linearly with increase of hydrogen peroxide from 3.17 ×10^-6 to 12.4 ×10^-6 mol/L. The detection limit of the proposed method was 1.1 ×10^-6 mol/L. It has been applied to determination of trace hydrogen peroxide in environmental water.